1. Field of the Invention
The present invention relates to a method of manufacturing a column and a bed of a machine tool and a structure thereof.
2. Description of the Related Art
FIG. 1 is an explanatory view showing a basic structure of a machine tool.
A machine tool indicated generally by reference numeral 1 has a saddle 20 supporting a machining head 10 capable of vertical movement, and the saddle 20 is supported by a column 30 capable of horizontal movement.
The column 30 has a motor 40 and moves on a bed 50 in the longitudinal direction. The bed 50 has a construction that a pair of structures are connected to each other by a beam 60.
FIG. 2A shows a conventional manufacturing process of can manufacturing constituting the bed 50 of the machine tool.
A material is cut off in step S10. When plasma fusing is used as means for cutting, for example, a dimensional tolerance is approximately ±1 mm to the fusing of 1000 mm.
The cut off material is provisionally assembled in step S11 and welded in step S12. In step S13, distortion generated by welding is removed. For example, in a lengthy structure with the whole length of approximately 8 m, distortion of not less than 10 mm is normally generated. Moreover, the distortion removal is a work requiring a long time labor by a worker with an extremely advanced skill. This structure is conveyed to annealing equipment in step S14 and annealed in step S15. A shot treatment is applied to the annealed structure, which is conveyed to machining equipment in step S17, given machining in step S18 and completed into the bed 50. This machining has a maximum machining range of not more than 4 m even in a relatively generally-used large-sized machine, and a place for machining is extremely limited for a large-sized work piece exceeding this size.
Construction of a machine tool in a welding can manufacturing structure is disclosed in non-patent documents of “Design Principle of Machine Tool” (1971) written by F. Koenigsberger, translated by Susumu Shiozaki and published by Yokendo and a magazine, “Applied Mechanical Engineering,” Special Feature Welded Structure Design, issued on Mar. 1, 1970, Vol. 11, No. 3.
Since a bed or the like of a machine tool is a large-sized structure, conveyance requires labor, and equipment such as a large-sized annealing furnace is needed.
Also, equipment for machining needs a large-sized machine and the number of processes becomes huge. Production time takes a couple of months or more using a conventional process.
An object of the present invention is to provide a method of manufacturing a structural body such as a column and a bed of a machine tool solving the above problems and a structure produced by this manufacturing method.